Questions tagged [sexual-reproduction]

Reproduction involving two morphologically distinct gametes, such as sperm and egg, where offspring inherit genes from two parents.

21 questions with no upvoted or accepted answers
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398 views

Can any animal ejaculate at will without physical contact?

Note: In this question, I'm asking about animals that have a penis that functions very similarly to humans. I've read some animals have dramatically different methods of copulation and physiologies, ...
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In bacterial conjugation, how do F+/F- cells detect each other?

I've just learnt about bacterial conjugation and while it is interesting info about early sexual activity in microbes, one aspect confuses me and doesnt seem to be mentioned in the material I read: ...
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58 views

Number of alleles' variations in a mushroom that has over 20,000 sexes

I am trying to understand the mating behavior of a particular species of fungi known as Schizophyllum commune, or the split-gill. I found a blog post that explains the mechanisms that define the ...
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134 views

Role of neuraminidase in preventing polyspermy in humans

Neuraminidase is a hydrolytic enzyme present in the acrosome of human sperm. It removes neuraminic acid (salic acid) from glycoproteins. I have read in a book that due to this reason it (the enzyme) ...
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463 views

Motile egg cells

According to the Wikipedia article on anisogamy, some types of this form of sexual reproduction involve motile egg cells, i.e. they're capable of movement under their own power, just like sperm cells. ...
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31 views

Extremely Scientific Sexual Education Material?

I'm trying to prepare material for 'the talk' about sex and reproduction. I know there's plenty of great books and resources out there for young readers, which I'll use to start with, but I'm also ...
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85 views

Does increased calorie intake cause increase in libido in humans?

I'm interested in the effect of increased calorie intake on sex hormones and chosen mating strategy in humans. I'm aware that humans have a dual mating strategy - somewhere between pair bond and ...
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1answer
94 views

Why spermatogenesis is an independent process while formation of ovum is dependent on fertilization by sperm?

At the time of ovulation,secondary oocyte is arrested at Metaphase II and goes into the fallopian tube.If fertilization occurs, sperm binds with secondary oocyte and releases Anaphase promoting factor ...
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53 views

Polyandry in birds

The WP article on Bateman's principle states “Until recently, most bird species were believed to be sexually monogamous. DNA paternity testing, however, has shown that in nearly 90% of bird species, ...
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79 views

What are the (statistically) normal pH levels in the most-outer part of human sexual organs?

What are the (statistically) normal pH values of the outer skin/epidermis of human sex organs (groin/crotch) in the male and female? e.g male testes, female vulva, male glans, the enveloping epiderm, ...
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44 views

How diverse are the sperm cells of an individual male due to random mutations?

Due to the sheer number of sperm cells in an individual and the rate of mutations, are they likely to be incredibly diverse and encompass most of what we see across our species? For instance would it ...
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606 views

What is the weight of a single human sperm (spermatozoon) compared to a single human egg

While the difference in dimension is well covered, I have been unable to find the mass measurements of each.
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98 views

At what level of relation does inbreeding become dangerous?

Inbreeding within first cousins appears to have an established history of dangers, and anything closer than that relationship also. However, how distantly related do two individuals have to be for ...
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879 views

Location of male and female reproductive organs in fern (prothallus)

I can't seem to find an authoritative answer to this anywhere else online. Basically, my school text-book says the antheridium (male organ) is located on the lower surface of the fern prothallus and ...
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117 views

Why male gametes doesn't go through antipodal cells in chalazogamy

Male gametes in double fertilisation enter the embryo sac through synergid cells even in chalazogamy i.e. when polen tube enters the ovule through chalazal end. Regarding the fact that compatibility ...
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Flowers in Arachis hypogea, are they clestogamous or chasmogamous?

I have seen the flowers of groundnut, they open and remains open for one day, so they should be chasmogamous, but in my school book, they mentioned it as clestogamous, and I searched for it in ...
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Human children with sex abnormalities due to food packaging and river pollutants?

Some news sites are highly vocal about transgender news articles, and also sometimes report hormonal issues due to pollution, like sex-changes in fish and low sperm counts in men. Is there any ...
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241 views

How does acetylcholine (aCh) cause erection?

I have read this article on physiology of erection : Activation of cholinergic receptors on the endothelial cell by acetylcholine or stretching of the endothelial cells as a result of increased ...
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42 views

Sexual Reproduction in Humans

Is the human egg cell (ova) considered motile? We know that is is not actively motile but it is transferred via the fallopian tube to the uterus. Does that make it motile?
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247 views

Sex and human's sexual urge.

Why is it necessary for humans to feel pleasure while having sex? Why is it that other animals don't need to experience it? Is it evolutionary ? Why do we mate for pleasure when it's so energy wasting/...
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Reproduction characteristics and Classification of Mules

DISCLAIMER Hi there, I'm new here, so please tell me if anything needs to be improved on the question, and feel free to retag it where necessary. So, on the whole, there are two questions about mules: ...